CSC 8310 Programming Languages Meeting 2 September 2/3, 2014.
CSC 243 – Java Programming, Spring, 2014 April 22, 2014 Week 13, JApplets.
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Transcript of CSC 243 – Java Programming, Spring, 2014 April 22, 2014 Week 13, JApplets.
CSC 243 – Java Programming, Spring, 2014
April 22, 2014Week 13, JApplets
JApplet
• JApplet, like JFrame, is an outer container into which you can add() JPanels and graphical controls.
• Unlike a JFrame, a JApplet is not an outer, first-class window. A JApplet appears inside a browser.
• A browser downloads a JApplet from a browser via an HTML page.
Example from Spring 2012
• ~parson/JavaLang/eventshuffle• SwingAppletShuffle.java• XYZshuffle.html• XYZshuffle2.html• XYZshuffle3.php– http://bill.kutztown.edu/~parson/XYZshuffle2.html– See code examples below.
Java code for the appletpublic class SwingAppletShuffle extends JApplet /** * init(), start(), stop() and destroy() are the four lifecycle * methods of a JApplet. The browser invokes init() to initialize any * applet-specific data structures *before* starting the applet. **/ public void init() { . . . } is invoked by browser when applet is loaded. public void start() { . . . } is invoked by browser to start applet. public void stop() { . . . } is invoked by browser to stop applet. public void destroy() { . . . } is invoked by browser to terminate applet.
Browser can cycle between start() and stop() calls to the applet.
Obtaining data in the Java code
• The applet can fetch parameters from the HTML page that loaded the applet.
String string1 = getParameter("string1");String string2 = getParameter("string2");
• The applet can open files for reading from the JAR file archive.
Scanner scanner = new Scanner(getClass().getResourceAsStream("english.0.txt"));
Ishuffle unshuffler = new XYZshuffle(scanner);
buildunix/windowsbuilds the JAR file
cd .. && export CLASSPATH=`pwd`cd ./eventshuffle && /bin/rm -f eventshuffle.jar
&& javac *.javacd .. && jar vcfm eventshuffle/eventshuffle.jar
eventshuffle/manifest.txt eventshuffle
This last step bundles all files in and below eventshuffle into archive eventshuffle.jar.
SwingAppletShuffle
• This example applet simply pops up a series of SwingShuffle JFrame objects, one per two-string solution, outside the browser frame.
• A more integrated solution would add() JPanels, etc. into the JApplet class itself, populating space inside the browser window.
• This example borrows logic from SwingShuffle.main in starting up frames.
gmake deploy
• Deploy by copying the html, php and JAR file (Java archive) that contains the class and data files for the applet to a directory accessible to a browser.
• cp *.html *.php eventshuffle.jar /www/faculty/parson/
• Run “gmake deploy” for details.